The Hematology/Oncology Division at the University of Pennsylvania has been formally engaged in organizing the training of academic scientists since 1978. Throughout this time, the goal of the training program has been to help outstanding candidates with an interest in hematology related research to prepare themselves for academic careers in laboratory and/or clinical investigation. The record of success of this training program has been admirable. Of the 64 trainees who completed their program, 41 (64%) presently hold full-time appointments at some 21 institutions throughout the United States, and all of these 41 individuals are engaged in either laboratory (-33%) or clinical (-66%) research. Further, approximately half of our former trainees have extramural research funding, with direct costs in Fiscal year '98 exceeding $7 million. Based on this tradition of excellence and success, we now seek to establish an additional, more highly focused training program in the area of stem cell biology and hematopoiesis. The justification for establishing this specialized training program is based on a number of factors. First, there has been a significant expansion of laboratories interested in hematopoiesis and stem cell biology in the Division of Hematology/Oncology and in the wider University community as well. The increase in laboratories and faculty who share hematopoiesis as a primary focus has created an exciting environment which is attracting increasing numbers of post-doctoral and pre-doctoral students to the University. Therefore, the second reason to establish this training program is demand by potential trainees. Finally, the work being carried out in these laboratories is highly translational with great relevance to the field of gene therapy and the treatment of cancer. Therefore, regardless of the sub-area in which students elect to train, it is deemed quite likely that individuals who complete this program will be much in demand as a result of their ability to compete successfully for extramural funding and for the potential contributions they may make to the advancement of medical care.